Right Whales Stage Comeback

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Right whales, a species once hunted to local extinction in the
waters around New Zealand, may be making a heartening return.

Researchers are studying whales that have recently reappeared
around New Zealand; and now, thanks to DNA fingerprinting,
scientists have begun to figure out where the whales are coming
from.

They suspect the
massive mammals are rediscovering a habitat that was erased
from whale memory more than 100 years ago.

Right whales wronged

Right whales once crowded the shores of New Zealand. Two
centuries ago, hundreds of the colossal whales gathered each
winter in the island's shallow, sandy bays to socialize, give
birth and nurture their
young calves in the temperate waters.

"You could throw a rock at them from the beach in a lot of
places," said Scott Baker, associate director of the Marine
Mammal Institute at Oregon State University.

Yet beginning in the 1820s, this idyllic habitat became the site
of abject slaughter. With the
dawn of the whaling age in the Southern Hemisphere, New
Zealand's bays, and eventually its surrounding waters, were
picked clean of the massive baleen whales.

Right whales, which can grow up to 60 feet (18 meters) long and
weigh up to 100 tons (equivalent to 56 pickup trucks), have rich
stores of blubber, a valued source of fuel and lamp oil during
whaling's heyday. In fact, their generous layers of blubber
earned the species its deceptively sunny moniker; whalers knew
the gigantic creatures were the "right" whales to kill

There are three distinct right
whale species : the North Atlantic, the North Pacific, and the
Southern right whale. The southern species roams the cool waters
of the sub-Antarctic in summer, and spends the winter near the
southern edges of South Africa, South America, Australia and New
Zealand — or did, once upon a time.

Some right whale populations recovered from decades of hunting —
those around Patagonia, for example, have made an impressive
comeback. Yet others remained mysteriously absent.

"We think that there were perhaps 30, maybe even up to 40,000
right whales in the larger New Zealand area in the time of early
European explorers," Baker said. "Throughout most of the 20th
century right whales essentially disappeared from the New Zealand
mainland."

So why did some populations recover and others didn't? Baker says
it may have to do with whale culture.

Lost knowledge

Unlike creatures such as monarch butterflies and birds, which
seem to have their migratory destinations imprinted onto their
DNA, right whales' brains don't appear to be hardwired with
directions back to their calving grounds. Instead the tradition
is passed from mother to calf. If an entire whale population is
killed off, as in New Zealand, so is the collective whales'
memory of where they go to have their young.

"Can we absolutely prove that? No. But these are social,
long-lived animals like humans and elephants, and we think
learning is a primary characteristic," Baker told
OurAmazingPlanet. "We think they're capable of changing these
traditions, and we think that's what we're seeing." [Related:
Quest
for Survival: Incredible Animal Migrations ]

In the early 1990s, aerial surveys revealed a crowd of right
whales in a bay in the Auckland Islands, about 300 miles (500
kilometers) south of New Zealand's mainland.

It turned out the whales were doing well there, despite calving
conditions that are colder than what the species typically
prefers, and the population was growing. Then, around 2005, a few
right whales began to appear around New Zealand — a vast,
inviting habitat. So where were those whales coming from?

Emma Carroll, a Ph.D. candidate at the University of Auckland in
New Zealand, spent several years venturing out in small boats to
take tiny whale biopsies, allowing her to make genetic profiles
of dozens of whales.

To collect samples, researchers shoot a whale with a metal dart,
which pulls out a plug of skin about the size of a pinky
fingernail.

"I think of it like a mosquito bite," Carroll said. Indeed, she
said, the whales don't seem to mind: "Sometimes they'll be asleep
and they don't even wake up."

Analysis revealed that seven females from the Auckland Island
population had begun to spend some winters in the
waters around New Zealand. So if this new habitat wasn't
taught to them by their own mothers — the way whales learn where
to go each winter — how did these whales stumble upon this new
habitat? And why are they returning?

"That's a really good question," Carroll told OurAmazingPlanet.
Researchers aren't sure how the whales have rediscovered their
old haunt, since memory of the place was likely lost with the
destruction of the local population.

One hypothesis is that conditions are getting too crowded around
the Auckland Islands. Is there, perhaps, a novelty gene, that
prompts some whales to strike out for new, roomier calving
grounds?

It's not clear, Carroll said, and more research is needed.

"Hopefully the whales that are going to the mainland are starting
a new tradition," Carroll said. "It's probably early days,
because we're not seeing them in huge numbers, but it's
promising. This is hopefully the vanguard of a proper recovery."

The findings are documented in the current edition of the journal
Marine Ecology Progress Series.